Brown et al. estimated the optimal length of a barrier for an 800-feet long row of grapes originated at a riparian zone. They found the length of the barrier declined with the effectiveness of the barrier crop and the profits of grapes relative to the barrier crop.The average profits per acre of grapes without PD were $5,230, and the baseline return from Christmas trees was $1,764 per acre. A barrier characterized by an effectiveness parameter of .05, .25, and 1.0, respectively, requires the grower to plant barriers only 69, 21, and 12-feet wide while reducing profit per acre on average from $5,230 to $4,856, $5,127, and $5,175, respectively. Without any barrier, the average profit per acre will decline to $3,054, as most of the rows near the riparian zone will be decimated. Thus, a barrier crop with a .25 effectiveness allows the grower to earn 98 percent of the profit earned in the case of no PD, while effectiveness of .05 leads to a loss of about 9 percent of the profits and, without a barrier, close to 40 percent of the average profits are lost to PD. Brown et al. also considered a mixed strategy that allows removal of the riparian zone in addition to riparian buffers. Their analysis assumed the price of $1,489 per ton of grapes as a baseline.The U.S. Fish and Wildlife Service,arandanos cultivo which has jurisdiction over riparian areas, opposes clearing vegetation.
The results of the simulations suggest that partially removing the host vegetation is sub-optimal regardless of society’s willingness to pay for riparian habitat. As the price of grapes rises, the break even social value of riparian vegetation increases linearly. With the bench price of $1,489 per ton, the removal of a 6 foot by 100 foot strip of riparian vegetation would be socially optimal if it provided less than $5,481 in environmental benefits. Alternatively, the value of the riparian zone strip is implicitly above $5,481 if the riparian zone is maintained. Recent research focuses on modification of the riparian zone, which will replace plants that are hosts to the bacterium and vector, while maintaining a riparian zone.This insect, and the PD it carries, is not just a threat to raisins and table and wine grapes, but it also has the potential to spread the disease to other important agricultural commodities. A joint state-federal plan has dedicated a total of $36 million to eradicate and prevent the spread of the glassy-winged sharpshooter , a new arrival in California. The federal government will allocate $22 million to augment state and private agricultural industry efforts to control the spread of the GWS and support research to find methods to cure PD. The GWS is active in warmer climates. It has already decimated most of the grapevines in Temecula in Southern California, and it is a problem in Los Angeles and Kern counties. Purcell’s simulations predicted that the GWS will spread to 15 grape-growing counties including Fresno and Tulare, which produced over $500 million worth of grapes in 2000.
The damage potential of PD spread through GWS can reach billions of dollars over time . GWS transmitted PD from oleanders and other host crops, especially citrus, and it is now being controlled by spraying pesticides in host citrus orchards adjacent to grape vines. The bacterium Xylella fastidiosa affects other crops besides grapes including almonds, peaches, and oleander. Brown et al. suggests that the net present value of potential damage is greater than $2 billion. Ongoing research aims to find biological control and biotechnology solutions to these pests, but for now the solution is through application of chemical pesticides.A driving factor behind pesticide regulation in the United States is the desire to protect consumers from harmful residues on food. The Food Quality Protection Act was unanimously passed by the U.S. Congress in 1996 and hailed as a landmark piece of pesticide legislation. It amended the Federal Insecticide, Fungicide, and Rodenticide Act , and the Federal Food, Drug, and Cosmetic Act , and focused on new ways to determine and mitigate the adverse health effects of pesticides. FQPA is different from past legislation; it is based on the understanding that pesticides can have cumulative effects on people, and that policy should be designed to protect the most vulnerable segments of the population. Recent research described below has investigated some of the impacts that FQPA’s provisions—many of which have yet to be fully implemented—may have on California growers and consumers. Pesticides are also regulated to mitigate the impact on worker health or the greater environment. Of particular interest to many Californian growers is the pending ban on Methyl bromide, an extremely effective soil fumigant that is being phased out because of its impact on the ozone layer.
The publication of the National Research Council report Pesticides in the Diets of Infants and Children showed that pesticide residues have disproportionate effects on children. Children eat and drink more as a percentage of their body weight than adults; they also consume fewer types of food. These dietary differences account for a large part of the exposure differences between adults and children. The committee also found that pesticides have qualitatively different impacts on children because children are growing at such a rapid pace. This concern for the differential impact pesticides have on children is reflected in regulatory changes required by the FQPA. For instance, the “10X” provision of the FQPA requires an extra ten-fold safety margin for pesticides that are shown to have harmful effects to children and women during pregnancy. The FQPA has also resolved the “Delaney Paradox” created by the Delaney Clause of FFDCA. Prior to FQPA, the Delaney clause prohibited the use of any carcinogenic pesticide that became more concentrated in processed foods than the tolerance for the fresh form. This was supposed to protect consumer health, yet it had the paradoxical effect of promoting other non-carcinogenic pesticides that created other health risks for consumers. FQPA standardizes the tolerances for pesticide residues in all types of food, and looks at all types of health risks. The federal Environmental Protection Agency must now ensure that all tolerances are “safe,” defined as “a reasonable certainty that no harm will result from aggregate exposure to the pesticide” . Historically, pesticide exposure was regulated through single pathways, either through food, or water, or dermal exposure. Now the EPA must consider all pathways of pesticide exposure, including cumulative exposure to multiple pesticides through a common mechanism of toxicity. This means that even though pesticides may be sufficiently differentiated that they are used on different crops to control different pests, they can have similar health effects on people. The result is that in some instances, pesticide tolerances for seemingly different insecticides must be regulated together based on their cumulative effects. When FQPA was first signed into law, 49 Organophosphate pesticides were registered for use in pest control throughout the United States, and accounted for approximately one third of all pesticide sales .
OP insecticides are highly effective insect control agents because of their ability to depress the levels of cholinesterase enzymes in the blood and nervous system of insects. It has been suggested that while dietary exposure to a particular OP may be low,maceteros grandes reciclados the cumulative effects of simultaneous exposure to multiple OP insecticides could cause some segments of the U.S. population to exceed acceptable daily allowances . Reducing the risk from these aggregate effects is specifically addressed in the FQPA and is one of the reasons the EPA has chosen OP pesticides for the first cumulative risk assessment. Due to their popularity and widespread use, many in the agricultural community are worried about FQPA implementation resulting in increased restrictions on OP pesticides. By the time EPA released the Revised OP Cumulative Risk Assessment in 2002, 14 pesticides had already been canceled or proposed for cancellation, and 28 others have had considerable risk mitigation measures taken . Risk mitigation may include: Limiting the amount, frequency, or timing of pesticide applications; changes in personal protective equipment requirements ; ground/surface water safeguards; specific use cancellations; and voluntary cancellations by the registrant. Economic theory suggests that these increased restrictions and cancellations from the eventual implementation of FQPA will result in a reduced supply of commodities currently relying on OP pesticides for pest control. This will result in higher prices for consumers and a lower quantity sold. In order to estimate the possible welfare effects on the state of California, University of California researchers conducted a study on the effects of a total OP pesticide ban on 15 crops. The estimated price and quantity changes are presented in Table 1. Results of the economic analysis suggest that the total loss to producers and consumers in California from banning all OP use will be approximately $200 million. There is significant uncertainty as to the final level of OP restrictions; this is only an order or magnitude estimate of the effects. However, these effects only represent about 2 percent of the total revenue generated by the 15 crops studied in California. While the overall effects seem small, they may be more intense in some segments than others. The researchers found that the degree of impact rests on the effectiveness of alternative pest control strategies producers have to choose from when faced with an OP ban. In some cases, OP pesticides have no close substitute, and cancellation will have larger effects. For instance, the losses in broccoli, one of the crops most sensitive to an OP ban, are driven by the lack of an alternative insecticide to treat cabbage maggot.As illustrated above, it is generally true that removing a pesticide from the production process will result in an increase of the price of the treated commodity. If consumers respond to the increased prices by reducing consumption of the affected fruits and vegetables , they may suffer a loss of health benefits associated with the change in consumption.
Scientific evidence is accumulating which shows a protective effect from fruits and vegetables in the prevention of cancer, coronary heart disease, ischemic stroke, hypertension, diabetes mellitus, diverticulosis, and other common diseases. The level of protection suggested by these studies is often quite dramatic. A recent review of several studies found that “the quarter of the population with the lowest dietary intake of fruits and vegetables compared to the quarter with the highest intake has roughly twice the cancer rate for most types of cancer” . Negative health outcomes from a change in dietary behavior may offset the direct health benefits of a pesticide ban, such as reduced exposure to carcinogenic residues on produce. A recent study by Cash investigates the possible magnitude of such offsetting health effects. Using data on what over 18,000 people eat and previous findings on how people respond to changes in the price of fruits and vegetables, the author simulated some of the health effects of a small increase in produce prices. Specifically, Cash examined the effects of a one-percent increase in the price of broad categories of fruits and vegetables on coronary heart disease and ischemic stroke, twoof the most common causes of death in the United States. The results are reported in Table 2.For a one percent increase in the average price of all fruits and vegetables, the simulations indicate an increase of 6,903 cases of coronary heart disease and 3,022 ischemic strokes. In order to offset these 9,925 cases in a population of 253.9 million people, a pesticide action would have to prevent 1 in 25,580 cancers. This is almost four times as protective as the mean risk of pesticide uses that were banned between 1975 and 1989 . Although these results can not be applied directly to most individual pesticide bans—which typically only affect the price of a few crops—the study shows that pesticide regulations that reduce relatively small risks at high cost may actually have a negative impact on overall consumer health. Furthermore, the research also suggests that low-income consumers may be the hardest hit by the negative health impacts of price-induced dietary changes, whereas high-income consumers tend to reap the greatest direct benefits from reduced residue exposures. Economic theory tells us that regulatory intervention is justified in the presence of market failures. In the case of pesticide residues on food, the two most salient sources of failure are externality and incomplete information.